The present invention relates to roller bearings and a roller chain incorporating the roller bearings.
Conventionally, Japanese Unexamined Patent Application, First Publication No. Sho. 62-4122 (Japanese Examined Patent Application, Second Publication No. Hei. 4-78523) discloses a roller chain incorporating the roller bearings. FIG. 22 is a cross-sectional view of the roller chain disclosed in the above-mentioned Japanese Unexamined Patent Application, First Publication No. Sho. 62-4122. In the roller chain 1 shown in FIG. 22 a plurality of rollers 4 for bearing are disposed on an outer periphery of a bush 3 whose both ends were connected to a pair of inner link plates 2, a roller 5 is attached to the rollers 4 so as to surround the rollers 4, and a thrust bearings receiving plate 6 is intervened in a space between the roller 5 and the inner link plate 2. Further, a pair of outer link plates 7 is disposed outside the inner link plates 2 and the pair of outer link plates 7 is connected to each other by means of a pin 8 that penetrates the bush 3. On the both ends of the roller 5 are integrally formed inward collars 5a, which hold and guide the rollers 4. Further, the space between the roller 5 and the bush 3 is filled with a lubricant such as grease or the like. In the roller chain 1, the roller 5 functions as an outer ring of the roller bearings, the plurality of rollers 4 function as a rolling body of the roller bearings and the bush 3 functions as an inner ring of the roller bearings. Therefore, the roller 5, the rollers 4 and the bush 3 constitute the roller bearings.
As another conventional example, Japanese Unexamined Utility Model Application, First Publication No. Hei. 2-7219 (Japanese Examined Utility Model Application, Second Publication No. Hei. 7-12327) discloses a roller chain incorporating the roller bearings. FIG. 23 is a cross-sectional view of the roller chain disclosed in the above-mentioned Japanese Unexamined Utility Model Application, First Publication No. Hei. 2-7219. In the roller chain 1xe2x80x2 shown in FIG. 23 a plurality of rollers 4xe2x80x2 are disposed on an outer periphery of a bush 3xe2x80x2 whose both ends were connected to a pair of inner link plates 2xe2x80x2, a roller 5xe2x80x2 is attached to the rollers 4xe2x80x2 so as to surround the rollers 4xe2x80x2, and a thrust bearings receiving plate 6xe2x80x2 is intervened in a space between the roller 5xe2x80x2 and the inner link plate 2xe2x80x2. Further, a pair of outer link plates 7xe2x80x2 is disposed outside the inner link plates 2xe2x80x2 and the pair of outer link plates 7xe2x80x2 is connected to each other by means of a pin 8xe2x80x2 that penetrates the bush 3xe2x80x2. The roller 5xe2x80x2 has not inward collars 5a on the both ends of the roller 5xe2x80x2 but the inner and outer peripheries of the roller 5xe2x80x2 are straight. The rollers 4xe2x80x2 are held and guided between a pair of thrust bearings receiving plates 6xe2x80x2. Further, the space between the roller 5xe2x80x2 and the bush 3xe2x80x2 is filled with a lubricant such as grease or the like. In the roller chain 1xe2x80x2, the roller 5xe2x80x2 functions as an outer ring of the roller bearings, the plurality of rollers 4xe2x80x2 function as a rolling body of the roller bearings and the bush 3xe2x80x2 functions as an inner ring of the roller bearings. Therefore, the roller 5xe2x80x2, the rollers 4xe2x80x2 and the bush 3xe2x80x2 constitute the roller bearings.
Further, conventionally the general roller bearing offers a retainer incorporating type and a retainer-unused type. The retainer that holds and guides the rollers generally has a pocket that holds and guides the whole each roller.
However, the roller chain 1 shown in FIG. 22 has the following problems. That is,
(1) The rollers 4 are only accommodated between the roller (outer ring) 5 and the bush (inner ring) 3, freely, and contact is generated between the rollers 4. Accordingly, wear is generated whereby a smooth rotation of the roller 5 is suppressed.
(2) Collision noises are generated on the contact between the rollers 4, and repeated impacts can generate a fatigue fracture.
(3) When a thrust load is applied to the roller 5, a skew (the slanting of the rollers 4 with respect to the proper rotational axis) is generated, and the collar 5a rubs against the roller 4. Accordingly, the rollers 4 are locked at an early stage, resulting in suppressing a smooth rotation of the roller 5.
(4) By sliding of the inner side of the collar 5a in the both ends of the roller 5 on the end face of the roller 4 the collar 5a rubs against the roller 4, resulting in suppressing a smooth rotation of the roller 5.
(5) Since the inner side of the collar 5a is a difficult place to enhance the surface roughness and perform heat-treatment in its manufacturing, the productivity of the roller is low.
(6) Since the collars 5a, 5a are integrally formed on the both ends of the roller 5, respectively, it is necessary to provide a clearance 5c (shown in an enlarged portion of FIG. 22) on a corner of a recess portion 5b in the roller 5 for preventing the interference of the roller 4 or for cutting and grinding the roller 5. Accordingly, it takes much time to cut and grind the roller 5 and the productivity of the roller 5 is low.
(7) In the assembling of the rollers 4 and the roller 5, the rollers 4 are previously installed in the recess portion 5b of the roller 5 and then they must be assembled. Thus, there is no flexibility and falling away of the roller 4 may be generated, which decreases the assembling capability.
The roller chain 1xe2x80x2 shown in FIG. 23 has the following problems. That is,
(8) Since the roller (outer ring) 5xe2x80x2 has no an inward collar (5axe2x80x2) the contact area between the roller 5xe2x80x2 and the thrust bearings receiving plate 6xe2x80x2 is small and a thrust load applied to the roller 5xe2x80x2 is locally received by the thrust bearings receiving plate 6xe2x80x2. Thus, the wear of the thrust bearings receiving plate 6xe2x80x2 tends to progress.
(9) Since the roller 5xe2x80x2 and the thrust bearings plate 6xe2x80x2 are completely independent of each other, the thrust bearings receiving plate 6xe2x80x2 cannot limit a skew generated in the rollers 4xe2x80x2 and the skew are easily generated.
(10) A gap is produced between the roller 5xe2x80x2 and the thrust bearings receiving plate 6xe2x80x2. Thus, a lubricant such as grease or the like easily leaks outside thereby to be exhausted so that the wear between the roller 5xe2x80x2 and the thrust bearings receiving plate 6xe2x80x2 rapidly progresses. Further, outside dust particles easily enters through the gap and the deterioration of lubricant and wear are promoted.
Further, in a general roller bearing in which the above-mentioned retainer was incorporated, the retainer has a pocket that holds and guides the whole each roller 4. Accordingly, the following problems occur. That is,
(11) Since each pocket embraces the whole each roller 4, the space between the rollers 4 is small, and since the retainer is complex the lubricant such as grease or the like cannot be uniformly held in the roller bearings and the lubricant holding amount is also small.
(12) The pocket that holds the whole each roller must be machined accurately and the production of the retainer is difficult and very expensive.
(13) Even each roller bearing using the same diameter, if the length of the roller is changed, needs a retainer having a pocket corresponding the changed length. Thus, a large number of types of the retainers must be kept and the parts management is no easy matter and costs a lot.
It is, accordingly, a general object of the present invention to provide roller bearings in which there is no contact between the rollers, a lubricant can be sufficiently held, a skew is not generated easily, and the roller bearings has a strong resistance to a thrust load and has sealing properties.
Another object of the present invention is to provide roller bearings that have excellent productivity and assembling capability.
Another object of the present invention is to provide a roller chain incorporating the roller bearings in which there is no contact between the rollers, a lubricant can be sufficiently held, a skew is not generated easily, and the roller bearings has a strong resistance to a thrust load and has sealing properties.
Still another object of the present invention is to provide a roller chain incorporating the roller bearings that have excellent productivity and assembling capability.
According to one aspect of the present invention, there is provided roller bearings wherein a plurality of rollers are disposed between an outer ring and an inner ring comprising substantially ring-shaped retainers disposed on both ends of said outer ring respectively, at least one of said retainers including a plurality of pockets for guiding at least a part of each of said rollers on the inner side of the retainer.
According to another aspect of the present invention, there is provided a roller chain incorporating the roller bearings wherein a plurality of rollers are disposed between a roller that functions as an outer ring and a bush that functions as an inner ring comprising a substantially ring-shaped retainer disposed on both ends of said roller respectively, said retainer including a plurality of pockets for guiding at least a part of each of said rollers on the inner side of the retainer.
According to still another aspect of the present invention, there is provided a roller chain incorporating the roller bearings wherein a plurality of rollers are disposed between a roller that functions as an outer ring and a pin that functions as an inner ring comprising a substantially ring-shaped retainer disposed on both ends of said roller respectively, said retainer including a plurality of pockets for guiding at least a part of each of said rollers on the inner side of the retainer.
In the above-mentioned aspects of the present invention, said retainer is preferably made of metal having wear resistance such as copper alloy or oleo-sintered alloy or resin having lubricating properties. Further, the retainer may be subjected to processing such as heat treatment, changing surface roughness, and forming a number of pits with a shot or a WPC to improve wear resistance of the retainer.
It is preferable that the pockets are formed on the retainer for at least one side of said roller. If the number of the pockets is further increased, the effects of the pockets can be obtained. One or more roller can be guided by one pocket.
Further, in the above-mentioned aspect of the present invention, preferably, the shape of said pocket is semicircular, circular, oval, polygonal, or similar to the end face of the roller. The pockets formed on both ends of said retainers may be asymmetric. The size of the pocket is not particularly limited, but a pocket having the same diameter as the roller or more can smoothly be rotated. Further, even if the pocket does not cover the whole outer periphery of the roller, if a part of the pocket comes contact with the roller and can guide the roller, the pocket can be used. Further, the pocket may even independently be connected to the rollers and the shapes of the pockets are not necessarily the same.
Further, it is preferable that the space between said outer ring and said inner ring is filled with a lubricant such as grease. However, even in a case where a lubricant such as grease or the like cannot be used, sliding between rollers does not occur. Thus, the chain roller or chain of the present invention can be used without a lubricant. Further, if heat-resisting material is used as the retainer, the roller chain or chain of the present invention can be used at a high temperature.
According to still another aspect of the present invention there is provided roller bearings-incorporated chain wherein a plurality of rollers are disposed between a bush that functions as an outer ring and a pin that functions as an inner ring comprising: engagement holes for the respective rollers formed along the respective central axes of said rollers; and a substantially ring-shaped retainer disposed on both ends of said roller respectively, said retainer including a guide portion for rotatably guiding said rollers while engaged in said engagement holes of said rollers. Further, the present invention can be applied to a rollers-incorporated cam follower and a roller follower.
According to the present invention, when the outer ring (roller) is rotated a roller that contacts with an inner periphery of the outer ring is automatically rotated and a rolling contact occurs. A retainer that guides the roller is rotated around an inner ring (a bush or a pin) by this automatic rotation of the roller. Then, since the roller is guided by the retainer, the contact and wear between the rollers are not generated and collision noises do not occur. Further, since there is a certain gap or space between the rollers, a lubricant such as grease or the like can be maintained in an appropriate amount and uniformly. Further, there is a space for a clearance (maintenance) against the intruders such as abrasive powder, dust particles and the like from outside, abrasive resistance is improved. The direction of rotation of the retainer is the same as that of the outer ring. Thus, a roller is regularly guided between the outer ring (roller) and the inner ring (bush or pin) and the outer ring is smoothly rotated.
Since the pocket that guides the roller does not grasp or fix the roller strongly, a slight slip between the roller and the retainer occurs according to the rotation of the roller. However, the roller and the retainer are hardly abraded. Further, although the radial load acts on the outer ring, the roller and the inner ring, it does not act on the retainer at all. Accordingly, the retainer is not abraded or broken by the radial load.
The number of rotation of the retainer is about half of the number of rotation of the outer ring irrespective of the diameter and the radius of revolution of the roller. Therefore, since the retainer is rotated with further largely decelerated than the rotation of the outer ring, when the outer roller receives a thrust load, sliding speeds of the retainer and the inner link plate are decreased. Thus, the wear of the retainer can be suppressed.